Scheduling resources for orthogonal frequency division multiple access uplink transmissions

ABSTRACT

This disclosure describes systems, methods, and devices related to a flexible connectivity framework. A first device may send a trigger frame to a second device. The first device may then receive an uplink bandwidth resource request from the second device. The first device may detect a high efficiency-long training field (HE-LTF) in the uplink bandwidth resource request. The first device may send an uplink multiuser trigger frame, and the first device may receive an uplink frame from the second device.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/088,932 filed on Apr. 1, 2016, which claims the benefit of U.S.Provisional Patent Application No. 62/203,272 filed on Aug. 10, 2015,the disclosures of which are incorporated herein by reference in theirentireties.

TECHNICAL FIELD

This disclosure generally relates to systems and methods for wirelesscommunications and, more particularly, to uplink bandwidth requesttransmissions sent to an access point (AP) on a shared resource unitusing cyclic shift diversity values.

BACKGROUND

Under development is a new IEEE 802.11ax standard, known as highefficiency wireless local area network (HEW), that is aimed to enhanceWi-Fi performance in indoor and outdoor scenarios. New HEW features areintroduced to improve the spectral efficiency and user throughputs ofWi-Fi in dense deployments. These new features will involve changes tothe physical (PHY) and medium access control (MAC) layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a network diagram illustrating an example networkenvironment of an illustrative orthogonal frequency division multipleaccess (OFDMA) uplink resource unit allocation architecture, inaccordance with one or more embodiments of the disclosure.

FIG. 2 depicts an illustrative schematic diagram of resource allocationrequests in an OFDMA uplink resource unit allocation system, inaccordance with one or more embodiments of the disclosure.

FIG. 3 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

FIG. 4 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

FIG. 5 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

FIG. 6 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

FIG. 7 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

FIG. 8 depicts an illustrative schematic diagram of channel trainingfields indexed by frequency and time, in accordance with one or moreembodiments of the disclosure.

FIG. 9 depicts a flow diagram of an illustrative process of a devicetransmitting an uplink bandwidth resource request from an access point(AP), in accordance with one or more embodiments of the disclosure.

FIG. 10 depicts a flow diagram of an illustrative process of an APdetecting and processing an uplink bandwidth resource request from adevice, in accordance with one or more embodiments of the disclosure.

FIG. 11 illustrates a functional diagram of an example communicationdevice that may be suitable for use as a device, in accordance with oneor more example embodiments of the disclosure.

FIG. 12 illustrates a block diagram of an example machine upon which anyof one or more techniques (e.g., methods) may be performed, inaccordance with one or more embodiments of the disclosure.

DETAILED DESCRIPTION

Example embodiments described herein provide certain systems, methods,and devices for providing a framework for flexible connectivity betweenwireless devices.

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

A design target for the HEW standard is to adopt methods to improve theefficiency of Wi-Fi, and specifically the efficiency in densedeployments of Wi-Fi devices, in places such as malls, conference halls,and public spaces where there may be several devices connected to asingle access point. HEW devices may use OFDMA-based distributed channelaccess (ODCA) techniques to access a downlink and uplink channel. Theuplink channel may be a channel accessed by at least one device to senddata to an AP, and the downlink channel may be a channel accessed by theAP to send data to at least one of the devices.

On the uplink channel based on ODCA, at least one user device may becommunicating with the AP and may be competing to access the channelwith other devices in a random channel access manner. For example, atleast two devices may access the channel to send an uplink bandwidthrequest at approximately the same time. In such a scenario, the uplinkbandwidth requests from the at least two devices may collide before theyreach the AP thereby making it difficult for the AP to distinguishbetween the uplink bandwidth requests. To prevent this from happening,each device may wait a random period of time before attempting to accessthe channel again to send its corresponding uplink bandwidth request.This may result in further collisions resulting in some devicesunsuccessfully attempting to access the channel in perpetuity.

On the downlink channel based on ODCA, the AP may send a trigger frameto the at least one device to prompt the device to send uplink bandwidthrequests. The trigger frame may comprise a preamble along with othersignaling, such as resource allocation, to coordinate the timing of theuplink bandwidth requests of the devices. For example, the trigger framemay comprise one or more resource units (RUs).

With ODCA, the AP transmits a trigger frame allocating the resources.The resources may be in time and/or frequency domain. Individual devicesmay use the allocated resource (e.g., 2 MHz of spectrum in a particularportion of a communication channel) to transmit their data to the AP.Therefore, with this approach, the devices may only transmit a narrowbandwidth signal in response to a trigger frame. However, the AP may notknow which devices are transmitting or how many have data to send.Consequently, the AP may not assign the resources based on, for example,cyclic shift diversity (CSD) values, for the devices requestingresources to transmit their data. Because the devices share the samefrequency resource unit (RU), the devices need to use different CSDvalues to tune the AP's automatic gain control (AGC) in order todistinguish the requests from different devices.

Example embodiments of the present disclosure relate to systems,methods, and devices for an OFDMA uplink resource allocation frameworkthat may enable two-phase uplink (UL) multi-user (MU) transmissions, aresource allocation phase, and a data transmission phase. The resourcerequest phase may be triggered by the AP, where the AP may poll thedevices to send a specific signal using UL OFDMA if the devices want tohave a transmit opportunity in the data transmission phase or in futureUL MU transmissions. In one embodiment, the characteristics of thesignal sent by the devices may enable the AP to identify the devices.For example, the AP may determine whether the devices are associateddevices or unassociated devices and whether the signal has random accesscharacteristics. An associated device is a device that may be assignedto a basic service set (BSS) and therefore uses a BSSID to transmit dataon an uplink. An unassociated device may be a device that is notassigned to a BSS and therefore does not use a BSSID to transmit data onan uplink. In some embodiments, a signal may be defined as a codesequence (line of the P-matrix) of the high-efficiency long trainingfield (HE-LTF) sent on a resource unit in frequency (26 tonesallocation) using UL OFDMA. This combination of a code and a frequencyresource unit may be associated with an ID, which is called the resourceblock ID (RBID). The AP may determine the identity of the device basedon the energy detection of the code and frequency unit (e.g., RBID). TheAP can acknowledge to the devices that it received the resourcerequests. The data transmission phase is a scheduled UL MU transmission,which may start with the AP sending a trigger frame to announce theidentity of the devices that will transmit in the UL MU transmission,and other information like the allocated resources.

In some embodiments, a device's uplink transmission may be sent withoutinterfering with other uplink transmissions of other devices using thesame frequency RU on a communication channel. Each device may utilizeone or more contention resource elements (CREs) to contend for thecommunication channel when a device wants to make an uplinktransmission. The CREs may be a frequency-time-space code unit, or afrequency-time code unit, that enables, at least in part, a device tosend its uplink transmission. Therefore, a CSD value may be assigned toboth units. If a device selects a CRE to send a signal requesting anuplink bandwidth, the device may use the CSD value assigned to the CRE.Alternatively, a range of CSD values may be defined ahead of time andprogrammed into the devices, by a user, thereby allowing the devices torandomly select a CSD value. In some embodiments, the AP may broadcastthe CSD values to be used by the devices instead of the devicesdetermining a CSD value. The content of the uplink bandwidth request maycomprise three phases. One phase may be a high efficiency-short trainingfield (HE-STF), a second phase may be a high efficiency-long trainingfield (HE-LTF), and a third phase may be a high efficiency data field.It is understood that the above descriptions are for purposes ofillustration and are not meant to be limiting.

FIG. 1 is a network diagram illustrating an example network environmentof an illustrative orthogonal frequency division multiple access (OFDMA)uplink resource unit allocation architecture, according to some exampleembodiments of the present disclosure. Wireless network 100 may includeone or more user devices 120 and one or more access point(s) (APs) 102,which may communicate in accordance with IEEE 802.11 communicationstandards, including IEEE 802.11ax (HEW). The user device(s) 120 may bemobile devices that are non-stationary (e.g., not having fixedlocations) or may be stationary devices.

In some embodiments, the user device(s) 120 and the AP 102 can includeone or more computer systems similar to that of the functional diagramof FIG. 11 and/or the example machine/system of FIG. 12.

One or more illustrative user device(s) 120 may be operable by one ormore user(s) 110. The user device(s) 120 (e.g., 124, 126, or 128) mayinclude any suitable processor-driven user device including, but notlimited to, a desktop user device, a laptop user device, a server, arouter, a switch, an access point, a smartphone, a tablet, a wearablewireless device (e.g., a bracelet, a watch, glasses, a ring, etc.) andso forth. Any of the user devices 120 (e.g., 124, 126, or 128) may beconfigured to communicate with each other and any other component of thewireless network 100 via one or more communications networks 130 and 135wirelessly or wired.

Referring to FIG. 1, there is shown a network diagram illustrating anexample wireless network 100 for an OFDMA uplink resource allocationsystem, according to some example embodiments of the present disclosure.In this environment, the user devices 120, including the HEW userdevices, may communicate with each other and transmit data on anoperating channel. These user devices may randomly access the operatingchannel to transmit their data. However, there may be situations wherethe user devices may access the operating channel using assigned (orscheduled) resource units.

In the case of random access, an access point (e.g., the AP 102) maysend a random access trigger frame (e.g., the trigger frame 104)indicating that the resource units are available for random access suchthat the random access resource units may be selected by the userdevices (e.g., the user devices 124, 126, and/or 128) to send and/orreceive data. The resource units may be represented by RU1, RU2, . . . ,RUn, where “n” is an integer. These resource units may be arranged in asequence such that a user device may determine which resource unit wasselected when the user device is ready to transmit its data. Theseresource units may be resources in time domain, frequency domain, or acombination of time and frequency domains. The user device may use oneof these resource units in order to send data to an access point (e.g.,the AP 102). Consequently, when a user device 120 detects the triggerframe 104, the user device 120 may identify it as a random accesstrigger frame. This may be achieved by the access point setting anidentifier in the trigger frame or by other means to flag the triggerframe as a random access trigger frame. The user device 120 may thenselect a resource unit from the resource units referenced in the triggerframe 104 by which to transmit an uplink bandwidth request to the AP 102in UL bandwidth resource request 106. The selection of the resource unitmay be done by employing various embodiments of the present disclosure.

The user device(s) 120 may be assigned one or more resource units or mayrandomly access the operating channel. It is understood that a resourceunit may be a bandwidth allocation on an operating channel in a timeand/or frequency domain. For example, with respect to the AP assigningresource units, in a frequency band of 20 MHz, there may be a total ofnine resource units, each of the size of a basic resource unit of 26frequency tones. The AP 102 may assign one or more of these resourceunits to one or more user device(s) 120 to transmit their uplink data.

In accordance with some IEEE 802.11ax (HEW) embodiments, an AP 102 mayoperate as a master device which may be arranged to contend for awireless medium (e.g., during a contention period) to receive exclusivecontrol of the medium for an HEW control period. The master device maytransmit an HEW master-sync transmission at the beginning of the HEWcontrol period. During the HEW control period, the HEW devices (e.g.,the user devices 120) may communicate with the master device inaccordance with a non-contention-based multiple access technique. Thisis unlike conventional Wi-Fi communications in which devices communicatein accordance with a contention-based communication technique, ratherthan a multiple access technique. During the HEW control period, themaster device may communicate with HEW devices using one or more HEWframes. Furthermore, during the HEW control period, legacy devicesrefrain from communicating. In some embodiments, the master-synctransmission may be referred to as an HEW control and scheduletransmission.

Any of the communications networks 130 and 135 may include, but are notlimited to, any one of a combination of different types of suitablecommunications networks such as, for example, broadcasting networks,cable networks, public networks (e.g., the Internet), private networks,wireless networks, cellular networks, or any other suitable privateand/or public networks. Further, any of the communications networks 130and 135 may have any suitable communication range associated therewithand may include, for example, global networks (e.g., the Internet),metropolitan area networks (MANs), wide area networks (WANs), local areanetworks (LANs), or personal area networks (PANs). In addition, any ofthe communications networks 130 and 135 may include any type of mediumover which network traffic may be carried including, but not limited to,coaxial cable, twisted-pair wire, optical fiber, a hybrid fiber coaxial(HFC) medium, microwave terrestrial transceivers, radio frequencycommunication mediums, white space communication mediums, ultra-highfrequency communication mediums, satellite communication mediums, or anycombination thereof.

Any of the user device(s) 120 (e.g., the user devices 124, 126, 128),and the AP 102 may include one or more communications antennas. Acommunications antenna may be any suitable type of antenna correspondingto the communications protocols used by the user device(s) 120 (e.g.,the user devices 124, 126, and 128), and the AP 102. Some non-limitingexamples of suitable communications antennas include Wi-Fi antennas,Institute of Electrical and Electronics Engineers (IEEE) 802.11 familyof standards compatible antennas, directional antennas, non-directionalantennas, dipole antennas, folded dipole antennas, patch antennas,multiple-input multiple-output (MIMO) antennas, or the like. Thecommunications antenna may be communicatively coupled to a radiocomponent to transmit and/or receive signals, such as communicationssignals to and/or from the user devices 120.

Any of the user devices 120 (e.g., 124, 126, or 128) and the AP 102 mayinclude any suitable radio and/or transceiver for transmitting and/orreceiving radio frequency (RF) signals in the bandwidth and/or channelscorresponding to the communications protocols utilized by any of theuser device(s) 120 and the AP 102 to communicate with each other. Theradio components may include hardware and/or software to modulate and/ordemodulate communications signals according to pre-establishedtransmission protocols. The radio components may further have hardwareand/or software instructions to communicate via one or more Wi-Fi and/orWi-Fi direct protocols, as standardized by the Institute of Electricaland Electronics Engineers (IEEE) 802.11 standards. In certain exampleembodiments, the radio component, in cooperation with the communicationsantennas, may be configured to communicate via 2.4 GHz channels (e.g.,802.11b, 802.11g, 802.11n), 5 GHz channels (e.g., 802.11n, 802.11ac), or60 GHz channels (e.g., 802.11ad). In some embodiments, non-Wi-Fiprotocols may be used for communications between devices, such asBluetooth, dedicated short-range communication (DSRC), ultra-highfrequency (UHF) (e.g., IEEE 802.11af, IEEE 802.22), white band frequency(e.g., white spaces), or other packetized radio communications. Theradio component may include any known receiver and baseband suitable forcommunicating via the communications protocols. The radio component mayfurther include a low noise amplifier (LNA), additional signalamplifiers, an analog-to-digital (A/D) converter, one or more buffers,and a digital baseband.

FIG. 2 depicts an illustrative schematic diagram of resource allocationrequests in an OFDMA uplink resource allocation system, in accordancewith one or more embodiments of the disclosure. An access point may sendODCA trigger frame 202 at some time before ODCA station requests 204 aresent to the access point from one or more devices in response to theODCA trigger frame 202. The ODCA station requests 204 may contain one ormore ODCA requests each of which may be sent from an individual device.Under normal ODCA operation, if multiple devices submit ODCA requests(e.g., uplink resource requests) at the same time, and the devices areapproximately equidistant from the access point, the access point maynot be able to differentiate one request from the others because theywill arrive at the access point at the same time. The requests maycollide thereby preventing the devices from successfully sending theirrequests to the access point. If the devices use the systems and methodsdisclosed herein however, the requests will not collide even if thedevices are equidistant from the access point and they submit theirrequests at the same time.

FIG. 3 depicts an illustrative schematic diagram of an uplink bandwidthrequest, in accordance with one or more embodiments of the disclosure.

The uplink bandwidth request may comprise two phases. The first phasemay comprise at least two devices sending high efficiency short trainingfields (HE-STFs) 302. The second phase may comprise the at least twodevices sending high efficiency long training fields (HE-LTFs) 304. Ingeneral, there may be n devices, wherein n is any natural number, thatsend HE-STF and HE-LTF fields to an AP. The HE-STF may be sent by thedevices so that the AP can adjust the automatic gain control (AGC) ofits antenna to receive a signal from the corresponding device. Thesignal sent by a device in the HE-LTF may be used by the AP to train areceiver in the AP to adjust to the channel between the device and theAP, in order to detect the uplink bandwidth request. For example, theHE-LTF may contain information about the impulse response in the timedomain of the channel or the frequency response in the frequency domain,or information about both that the AP may use in order to separate thesignal sent by the device from the noise produced by the environmentbetween the device and the access point. If the AP has multiplereceiving antennas, it may use uplink multiuser multiple input multipleoutput (MU-MIMO) for receiving data from different devices. If an AP hasmultiple receiving antennas, the HE-LTF may be in the format of anuplink MU-MIMO channel training, which consists of orthogonal codes(e.g., P-matrix codes) applied across OFDMA symbols. The OFDMA symbolsmay be represented by the time access in FIG. 3. If data from therequesting devices is sent simultaneously and the AP has multipleantennas, it will use an estimate of the spatial channels correspondingto the different devices, to separate and receive the data from thedifferent devices, respectively.

HE-LTF 304 may comprise a content resource element (CRE) which is afrequency-time-space and/or a frequency-time-code unit that each devicetransmitting an uplink bandwidth request may use to identify itself withthe AP. For example, the CRE may be represented by a code in thefrequency domain and/or time domain. In some embodiments, a frequencyband may be divided into multiple resource units (RUs) for a requestingdevice to select. The RUs may correspond to frequencies over which anHE-LTF may be assigned, and may be used by a device to send an uplinkbandwidth request as explained below in FIG. 4.

In some embodiments, a legacy preamble may be sent before the HE-STF asshown in FIG. 4. The legacy preamble may include a legacy short trainingfield (L-STF) (e.g., the L-STF 402), a legacy long training field(L-LTF) (e.g., the L-LTF 404), and a legacy signal (L-SIG) (e.g., theL-SIG 406) field. The HE-STFs 408 and the HE-LTFs 410 may be equivalentto the HE-STFs 302 and the HE-LTFs 304. The L-STF 402 may comprisefields similar to those in the HE-STFs 408, but the L-STF 402 may beused by legacy devices and the HE-STFs 408 may be used by highefficiency devices. The L-LTF 404 may comprise fields similar to thosein HE-LTFs 410, but the L-LTF 404 may be used by legacy devices and theHE-LTFs 410 may be used by high efficiency devices. The legacy preambleis for holding the transmission of legacy devices (e.g., physical layerspoofing). In some embodiments, a high efficiency signal A field(HE-SIG-A) (e.g., the HE-SIG-A 508) may also be sent after a legacysignal (L-SIG) field (e.g., the L-SIG 506) as illustrated in FIG. 5. TheHE-SIG-A field may comprise a control information subfield including,but not limited to, the frequency band over which a device istransmitting, and a group identification (ID) identifying a group ofdevices to which the requesting device belongs to, requesting an uplinkbandwidth request or a device ID identifying the requesting device. TheHE-SIG-A field may also comprise a stream information subfieldindicating the number of locations of spatial streams that may be usedby the requesting device or a group of devices to which the requestingdevice belongs to. The HE-SIG-A field may further comprise an uplinkindication subfield indicating whether a physical protocol data unit(PPDU) that is carrying the HE-SIG-A field and any subsequent fields isdestined for an AP. The HE-SIG-A field may also comprise a multiuser(MU) information subfield, indicating whether a PPDU is a single user(SU) MIMO (SU-MIMO) PPDU or a multiuser (MU) MIMO (MU-MIMO) PPDU. TheHE-SIG-A field may also comprise a guard interval indication subfieldindicating whether a short or long guard interval is used in the PPDU,an allocation subfield indicating a band or channel (subchannel index orsubband index) allocated to each device in a bandwidth over which a PPDUmay be transmitted by the device, and a transmission power subfieldindicating a transmission power level for each channel identified in theallocation subfield. The HE-SIG-A field may be used by high efficiencydevices. HE-STFs 510 and HE-LTFs 512 may be equivalent to HE-STFs 302and 408 and HE-LTFs 304 and 410 respectively.

In some embodiments, the uplink bandwidth request may have a data field(e.g., HE data 606 and HE data 714) as illustrated in FIGS. 6 and 7. Thedata field may indicate the bandwidth size requested and/or part of thedevice ID associated with the device transmitting the uplink bandwidthrequest. The data field may also contain a value corresponding to theurgency of the request. For example, if a wireless device happens to bean Internet Protocol (IP) phone sending an uplink bandwidth request toconnect the IP phone to an emergency telephone number (e.g., 911 or112), then the AP may accept the IP phone's uplink request prior toaccepting another request for access to a webpage (e.g., The Wall StreetJournal). The HE-STFs 602 and the HE-LTFs 604 may be equivalent to theHE-STFs 302, 408 and 510 from FIGS. 3, 4 and 5 respectively. The HE-LTFs604 may be equivalent to HE-LTFs 304, 410, and 512 of FIGS. 3, 4, and 5respectively. The L-STF 702, L-LTF 704, L-SIG 706, and HE-SIG-A 708 maybe equivalent to L-STF 502, L-LTF 504, L-SIG 506, and HE-SIG-A 508 ofFIG. 5.

FIG. 8 depicts an illustrative schematic diagram of channel trainingfields indexed by frequency and time, in accordance with one or moreembodiments of the disclosure. In particular, FIG. 8 illustrates afrequency-time-code assignment 800 of at least one RU from RUs 802 froma frequency subchannel (not shown) and at least one OFDMA symbol fromthe OFDMA symbols 804 to at least one HE-LTF. RUs 802 correspond to eachcolumn of the frequency-time-code assignment 800. Thefrequency-time-code assignment 800 may represent the RUs and OFDMAsymbols that may be used by a device requesting an uplink bandwidthrequest. In some embodiments, a 20 MHz subchannel may be divided intomultiple RUs from which a device may select to send an uplink bandwidthrequest. For instance, HE-LTFs 304, 410, 512, 604, 712 of FIGS. 3, 4, 5,6 and 7, respectively, may correspond to a subset of RUs from the RUs802 for a given OFDMA symbol from the OFDMA symbols 804. For example,HE-LTFs 410 of FIG. 4 may correspond to the RUs 806 which are a subset(i.e., the first column) of all the RUs 802 in the frequency-time-codeassignment 800 and the OFDMA symbol assigned to HE-LTF(1).

A contention resource element (CRE) may be included in an HE-LTF, andmay carry a signal for identifying the requesting devices by the AP. Forexample, a code in the frequency domain and/or time domain can be sentin the CRE. The frequency and/or time location of the CRE and the codein the CRE can be associated with the requesting devices ID and/or otherinformation such as the requested bandwidth size. The code may be onerow or column of a P-matrix. The P-matrix can be replaced by other(orthogonal) matrices such as a Hadamard matrix or discrete Fouriertransform (DFT) matrix or any of its variants. The code may be sent inthe frequency domain (e.g., as in a DensiFi framework for uplink MU-MIMOtransmission). Alternatively, or additionally, the code can be sent inthe time domain using regular MIMO.

As explained above, the frequency band may be divided into RUs, andOFDMA symbols across time. Each RU in each OFDMA symbol can carrymultiple codes (e.g., up to eight codes). The code can be sent in thefrequency domain across subcarriers. Another code can be sent in thetime domain across multiple OFDMA symbols. Namely, each device can picka CRE from a frequency-time code domain to signal its request to an APfor an uplink bandwidth request. The codes are spread across time and/orfrequency. In some embodiments, the selection of the CRE can be relatedto the device ID, and in other embodiments the selection may be random.If the device randomly selects a CRE, the CRE index may be the temporaryID of the device during the uplink bandwidth request process. Forexample, the AP detects energy on the randomly selected CRE and uses theindex of the CRE in the subsequent scheduling frame for assigning uplinkresources to the requesting device. The RUs may be represented by thecolumns corresponding to the HE-LTFs in FIG. 8. Each RU can be encodedin one or more OFDMA symbols.

As explained above, when the AP receives signals from multiple devices,it needs to set its AGC according to the channel gains for each device.For example, the channel gains experienced by a signal sent from userdevices 124, 126, and 128 to AP 102 may correspond to channel gains A,B, and C respectively. There may be a single channel tap for eachchannel. If user devices 124, 126, and 128 are in close proximity to AP102, the arrival times of their signals are approximately the same. Inthis case, if the signals (e.g., HE-STFs and L-SIGs) are sent using awaveform that is a function of time (e.g., x(t)), then the receivedsignal may be the sum of the product of the channel gain and waveform ofall the transmitted signals (e.g., [A+B+C]x(t)). Therefore the channelgain may be A+B+C. This may be generalized to m different user devices(UDs) (i.e., UD₁, UD₂, UD₃, UD_(m)) with m unique channel gains (CGs)(i.e., the received signal may be Σ_(i=1) ^(m)[CG_(UD) _(i) ]x(t)),wherein m is a natural number. The channel gains may be random values,and therefore the sum of the channel gains may be added constructivelyor destructively at the AP 102. The signals transmitted after the HE-STFphase contain information necessary for the AP 102 to determine whichdevices are transmitting uplink bandwidth requests. Because the waveformused by the devices to transmit the remaining fields after the HE-STFphase, the AP 102 may set its AGC according to the sum of the power ofthe user devices, or the square root of the sum of the squares of thechannel gains associated with each user device (i.e., √{square root over(a²+b²+c²)}) instead of the sum of the channel gains (e.g., a+b+c). Inother words, the AP 102 may need to measure the total received power ofthe devices' signals instead of the superimposed magnitude. Consequentlythe devices must send different signals during the HE-STF phase.

In some embodiments, the user devices may use cyclic shift diversity(CSD) values to generate different signals for the HE-STF during theHE-STF phase. For example, each user device may be assigned a differentorthogonal code (e.g., a P-matrix code) in time and/or frequency, andeach code may be associated with a different CSD value. In someembodiments, the CSD values used in the IEEE 802.11n and IEEE 802.11axstandard may be used. Each code in each frequency-time-code resource maybe associated with a different CSD value. For the same frequency RU orCREs in the same frequency RU, the CREs in time and/or frequency domainsmay be associated with different CSD values. For example, for eight userdevices in the same frequency RU with eight different codes in the timedomain, the CSD values of the HE-STF phase may be (0, −400, −200, −600,−350, 650, −100, −750) nanoseconds as defined in the IEEE 802.11 acstandard. The user device using the first code or a spatial stream 1should use 0 nanoseconds, and the user device using the second code or aspatial stream 2 should use −400 nanoseconds.

In some embodiments, each user device may have multiple antennas,thereby requiring additional CSD values. The CSD values defined in IEEE802.11ac and/or IEEE 802.11n may be used. In other embodiments, the CSDvalues below may be used. For example, a user device may have sixantennas and it may use the fifth code or spatial stream 5. Thecorresponding CSD value for its first antenna may be −350 nanoseconds,and the remaining antennas on the user device may sequentially selectCSD values from a per-antenna CSD table (e.g., 0, −200, −25, −150, −175,−125), and apply them to a modulus operator to generate thecorresponding CSD values. Returning to the example, the CSD values forthe remaining antennas may be equal to the modulus of −350 with eachvalue in the per-antenna CSD table above (e.g., −mod((350+[200, 25, 150,175, 125]),750)=−550, 375, 500, 525, and 475 nanoseconds). Because eachuser device maintains a clock that is synchronized with the AP,assigning different CSD values enables each user device to transmit anHE-STF without it colliding with another user HE-STF. Consequently, theAP may distinguish each user device based on the timing with which itreceives the HE-STF which corresponds to the time in which each userdevice transmits its HE-STF.

In other embodiments, there may be two different sets of CSD values: onefor different spatial streams and the other for different antennas onthe same user device. The user device may first look up a per-stream CSDtable for a global CSD shift value for all of its antennas and then usea per-antenna CSD table to transmit an HE-STF. The CSD value of eachantenna may be determined by both the per-stream CSD table and theper-antenna CSD table. The CSD value from the per-antenna CSD table maybe added to the global CSD shift value from the per-stream CSD table. Ifthe sum of the two exceeds the range of the CSD values, a modulusoperation may be used to fold the sum back into the CSD value range.

Referring back to the example of FIG. 5, the L-SIG 506 may be used bylegacy user devices in an overlapping basic service set (OBSS) toreceive signals. Different CSD values may be needed for the legacy userdevices to send the L-STF 502, the L-LTF 504, the L-SIG 506, and theHE-SIG-A 508 since the user devices do not leverage afrequency-time-code assignment (e.g., the frequency-time-code 800) todistinguish one user device's transmission from another. Since thebandwidth of the L-STF 502, the L-LTF 504, the L-SIG 506, and theHE-SIG-A 508 may be 20 MHz, which differs from the RU size in theHE-STFs 510 and the HE-LTFs 512, the CSD values used in the L-STF 502,the L-LTF 504, the L-SIG 506, and the HE-SIG-A 508 may be different fromthose used in the HE-STFs 510 and the HE-LTFs 512. In some embodiments,the user devices may randomly pick CSD values for the L-STF 502, theL-LTF 504, the L-SIG 506, and the HE-SIG-A 508. In other embodiments,the user devices may reuse the CSD values associated with the code, theRU location, and/or the CRE location used in the request phase (i.e.,HE-LTF). If frequency domain codes are used, the CSD values of differentuser devices may be the same for the same RU because the CSD values maydegrade the orthogonality of the codes across the frequency.

In some embodiments in which devices are communicating with an AP, andhave line of sight with an AP, there may be some devices that arefarther away from the AP than other devices, and therefore the pathlosses experienced by the devices that are farther away may be differentthan the devices that are closer to the AP. In this case, the devicesthat are farther away may transmit an uplink bandwidth request with ahigher transmit power so that it is successfully received by the AP. Asa result, a transmission by the devices closer to the AP may besuccessfully received, but may interfere with the transmission of otherdevices that are farther away from the AP, if the devices closer to theAP and the devices farther from the AP are transmitting at the sametime. In other scenarios, some devices may have an object obstructing awaveform (i.e., a modulated signal) carrying an uplink bandwidth requestbeing sent to the AP, and therefore the path losses experienced by someof the devices may be different. For instance, some devices may have aline of sight with the AP, and others may not have a line of site withthe AP. As a result, the channel estimation parameters may be differentand consequently the signal-to-noise ratio (SNR) of the receiver at theAP may be different for the devices that have a line of sight and thosethat do not have a line of sight. In both scenarios, this may result insome devices unsuccessfully transmitting their uplink bandwidthrequests, thereby preventing these devices from communicating with theAP. In order to compensate for this issue, the AP may include a powertransmission control field in a trigger frame (e.g., the trigger 104 ofFIG. 1) soliciting the uplink bandwidth requests (e.g., the UL bandwidthresource request 106 of FIG. 1) from the devices that it communicateswith. For example, the AP may send a trigger frame to solicit uplinkbandwidth requests from the devices. After the devices receive thetrigger frame, each device sending an uplink bandwidth request mayadjust its transmission power so that the received power level at the APcorresponds to a specified power level in the trigger frame. The triggerframe may also include the transmission power level at which the triggerframe was transmitted from the AP to the devices, thereby enabling thedevices to calibrate their receivers by generating an estimate of thechannel. Because each station may adjust its transmission power to aunique transmission power level, the AP will be able to detect theuplink bandwidth requests from the different devices, without somedevices' uplink bandwidth requests going undetected. For example, if afirst device transmits an uplink bandwidth request at a firsttransmission power level, and a second device transmits an uplinkbandwidth request at a second transmission power level, wherein thefirst and second transmission power levels are not the same, the AP maysuccessfully receive both uplink bandwidth requests. In someembodiments, the AP may be able to assign a transmission power level perdevice such that the power level detected by a receiver in the AP mayenable the AP to determine which device has transmitted an uplinkbandwidth request. For instance, a processor in the AP may develop abijective relationship between each device communicating with the APthat may submit an uplink bandwidth request and a transmission powerlevel such that each device has a unique transmission power levelassigned to it. It is understood that the above descriptions are forpurposes of illustration and are not meant to be limiting.

FIG. 9 depicts a flow diagram of an illustrative process of a devicetransmitting an uplink bandwidth resource request from an AP, inaccordance with one or more embodiments of the disclosure. The flowdiagram may be a method implemented by at least one processor on a userdevice (e.g., the user devices 124, 126, or 128 of FIG. 1) to generate asignal that may be used to transmit an uplink bandwidth resourcerequest. In particular, FIG. 9 illustrates a sequence of steps that maybe executed, in the form of computer readable instructions, by aprocessor in the user device, to implement an uplink bandwidth resourcerequest as described below. The instructions may or may not be executedin the same sequence as illustrated in FIG. 9.

At block 902, the processor may receive a trigger frame (e.g., thetrigger 104 of FIG. 1) from an AP (e.g., the AP 102 of FIG. 1)soliciting an uplink bandwidth resource request. The trigger frame maycomprise a field indicating to the user device that a time period forrequesting uplink bandwidth resource requests has been initiated by theAP. In some embodiments, the user device may detect energy and/or poweron a given frequency which may be reserved for indicating to the devicethat the time period for requesting uplink bandwidth resource requestshas begun. In some embodiments, the trigger frame may also solicit powersaving poll information and/or channel assessment information from theuser device along with the uplink bandwidth resource requests. Forinstance, the trigger frame may comprise a first field for solicitinguplink bandwidth resource requests, a second field for soliciting powersaving (PS)-poll information, and a third field for soliciting channelassessment information. If the trigger frame comprises the second fieldfor soliciting PS-poll information from the device, the PS-poll fieldmay be sent to determine which devices are in a power save state andwhich devices are not in a power save state. If the trigger framecomprises the third field for soliciting channel assessment information,the channel assessment information requested from the device may includeany channel estimates generated by the device (e.g., measurement of theimpulse response of the channel between the AP and the device). In someembodiments, the user device may detect energy and/or power on a givenfrequency which may be reserved for indicating to the device whatinformation is being solicited in the trigger frame (e.g., an uplinkbandwidth resource request, PS-poll information, and/or channelassessment information).

At block 904, the processor may then determine if the user device isassociated with the AP or unassociated with the AP. A device may beassociated with an AP if it belongs to a service set with acorresponding association identifier (AID) assigned to it. If the deviceis associated with the AP, the processor may select an RU and acorresponding code from a set of RUs assigned to associated devices(block 906). The set of RUs assigned to associated devices may be asubset of the frequencies over which the RUs may be assigned in afrequency-time-code assignment (e.g., the frequency-time-code assignment800 of FIG. 8). For instance, a 20 MHz bandwidth may be divided intonine RUs. Six RUs may be reserved for associated devices to transmituplink bandwidth resource requests, and the remaining three RUs may bereserved for unassociated devices to transmit uplink bandwidth resourcerequests. As an example, the RUs 806 of FIG. 8 may comprise nine RUsspanning a 20 MHz bandwidth, resulting in each RU comprising 2 MHz ofbandwidth. And a corresponding OFDMA symbol may be represented byHE-LTF(1) from the OFDMA symbols 804 of FIG. 8. The processor in anassociated device may select from the RUs corresponding to the firstnine RUs starting from the topmost RU of RUs 806 to the ninth RU of RUs806. The remaining three RUs starting at the seventh RU of RUs 806 tothe bottom most RU of RUs 806 may be used for unassociated devices. Acode corresponding to the RU, or the location of the RU in the totalallocable bandwidth (e.g., 20 MHz), may be used by the processor toselect an RU. For example, a first code may correspond to the locationof the first RU, and a second code may correspond to the location of thesecond RU, etc.

If the device is unassociated, the processor may randomly select an RUand a code corresponding to the RU from a set of RUs not assigned to theassociated devices (block 908). Returning to the example above, one ofthe three remaining RUs of the RUs 806 may be randomly selected by theprocessor to transmit its uplink bandwidth resource request on OFDMAsymbol HE-LTF(1).

Additionally, and/or alternatively, a code may be transmitted in anOFDMA symbol, as explained above, corresponding to a set of RUs. Forexample, a code may be transmitted corresponding to the OFDMA symbolassociated with HE-LTF(1) of the OFDMA symbols 804 of FIG. 8 and an RUfrom the RUs 806 of FIG. 8. Thus instead of a code being transmittedcorresponding to the RU, a code may be sent corresponding to the OFDMAsymbol associated with the RU, or the code corresponding to the RU maybe sent in addition to a code corresponding to the OFDMA symbol. Thismay be referred to as a frequency-time-code, wherein the codecorresponding to the RU is a frequency code sent across at least onesubcarrier in a frequency domain, and the code corresponding to theOFDMA symbol is a time code sent across at least one OFDMA symbol in atime domain.

After the processor selects the RU and corresponding code, the processormay determine a power transmission level, at block 910, that the devicemust transmit its uplink bandwidth resource request to which correspondsto the code selected in either block 906 or block 908. After determiningthe transmission power level, the processor may then determine if alegacy preamble should be included in the uplink bandwidth resourcerequest in block 912. The processor may determine whether or not alegacy preamble should be sent to the AP based on whether or not thedevice is a legacy device or an HE device. If the device is a legacydevice, the processor may transmit the uplink bandwidth resource requestin an L-LTF (e.g., the L-LTF 404 of FIG. 4) within a legacy preamblecomprising an L-STF, an L-LTF, and an L-SIG (e.g., the L-STF 402, theL-LTF 404, and the L-SIG 406 of FIG. 4) using the determinedtransmission power level and a CSD corresponding to the code (block914). In some embodiments, the processor may randomly select a CSDvalue, as explained above, for the L-LTF. For instance, a set of RUs,comprising at least one RU, may be reserved for the processor to use tosend its uplink bandwidth resource requests. In particular, theprocessor may use an RU that is used simultaneously by other legacydevices to send its uplink bandwidth resource request. Each device mayrandomly select and use a unique CSD value, separated in time, toprevent collisions of the L-LTFs. Accordingly the processor may randomlyselect, or be assigned, a CSD value based on a synchronization of theprocessor's clock with the AP to prevent the processor from transmittingan L-LTF at the same time the other device's processors may transmit anL-LTF.

If the device is an HE device, then the processor may transmit theuplink bandwidth resource request without the legacy preamble using thedetermined transmission power level and the corresponding code in anHE-LTF (e.g., one of the HE-LTFs 410 of FIG. 4) (block 916). In someembodiments, the processor may execute computer-readable instructionscorresponding to block 912 before block 904 or after block 904 andbefore block 910. It is understood that the above descriptions are forpurposes of illustration and are not meant to be limiting.

FIG. 10 depicts a flow diagram of an illustrative process of an APdetecting and processing an uplink bandwidth resource request from adevice, in accordance with one or more embodiments of the disclosure. Inparticular, FIG. 10 illustrates a sequence of steps that may beexecuted, in the form of computer-readable instructions, by a processorin the AP, to detect and process an uplink bandwidth resource requestreceived from a device as described below. The instructions may or maynot be executed in the same sequence as illustrated in FIG. 9.

At block 1002, a processor in the AP (e.g., the AP 102 of FIG. 1) mayexecute computer-readable instructions that cause it to send a triggerframe to a device soliciting an uplink bandwidth resource request from adevice. After transmitting the trigger frame, the AP may receive anuplink bandwidth resource request from the device at block 1004 and maydetermine if a legacy preamble is detected in the bandwidth resourcerequest (block 1006). The legacy preamble may comprise an L-STF, anL-LTF, and an L-SIG (e.g., the L-STF 402, the L-LTF 404, and the L-SIG406 of FIG. 4) as described above. If a legacy preamble is detected, theprocessor may detect energy and/or power on the L-STF at block 1008, andset an automatic gain control (AGC) of a transceiver electronicallycoupled to the processor at block 1010. The L-STF may comprise at leastone signal that the transceiver can use to train itself (i.e., set theAGC) to recognize signals from the device that it received the legacypreamble from. After setting the AGC, the processor may detect energyand/or power corresponding to the L-LTF in the uplink bandwidth resourcerequest (block 1012). As explained above, the CSD values may be used bylegacy devices to transmit portions of the legacy preamble (e.g., theL-STF and the L-LTF). In particular, the processor may receive a firstCSD value corresponding to the L-STF and a second CSD valuecorresponding to the L-LTF. In some embodiments, the CSD value may beassociated with a code or an RU location or CRE location used by HEdevices to transmit an HE-LTF.

If a legacy preamble is not detected at block 1006, the processor maydetect energy and/or power on an HE-STF (e.g., one of the HE-STFs 710 ofFIG. 7) (block 1014). The HE-STF may comprise at least one signal thatthe transceiver can use to train itself (i.e., set the AGC) to recognizesignals from the device based on the HE-STF. The processor may set theAGC after receiving the HE-STF (block 1016). In some embodiments, theprocessor may use the CSD values to set the AGC as explained above.After setting the AGC, the processor may detect energy and/or powercorresponding to an HE-LTF in the uplink bandwidth resource request atblock 1018 and a code corresponding to an RU on which the uplinkbandwidth resource request was transmitted and received. The uplinkbandwidth resource request may be received with a certain power levelcorresponding to the code. The code may correspond to the RUs associatedwith an associated device or an unassociated device. Thus a first set ofcodes may correspond to RUs associated with associated devices and asecond set of codes may correspond to RUs associated with unassociateddevices.

Additionally, and/or alternatively, a code may be received in an OFDMAsymbol as explained above corresponding to a set of RUs. For example, acode may be received corresponding to the OFDMA symbol associated withHE-LTF(1) of the OFDMA symbols 804 and an RU from the RUs 806 of FIG. 8.Thus instead of a code being received corresponding to the RU, a codemay be received corresponding to the OFDMA symbol associated with theRU, or the code corresponding to the RU may be received in addition to acode corresponding to the OFDMA symbol. This may be referred to as afrequency-time-code, wherein the code corresponding to the RU is afrequency code sent across at least one subcarrier in a frequencydomain, and the code corresponding to the OFDMA symbol is a time codesent across at least one OFDMA symbol in a time domain.

After an uplink bandwidth resource request is detected in an L-LTF atblock 1012 or in an HE-LTF at block 1018, the processor may transmit anUL MU trigger frame at block 1020 to initiate a data transmission phaseby the device. At block 1022, the processor may receive at least one ULframe from the device comprising data transmitted by the device (e.g.,one of the HE data 606 of FIG. 6 or the HE data 714 of FIG. 7). It isunderstood that the above descriptions are for purposes of illustrationand are not meant to be limiting.

FIG. 11 shows a functional diagram of an exemplary communication station1100 in accordance with some embodiments. In one embodiment, FIG. 11illustrates a functional block diagram of a communication station thatmay be suitable for use as an AP 102 (FIG. 1) or a user device 120(FIG. 1) in accordance with some embodiments. The communication station1100 may also be suitable for use as a handheld device, a mobile device,a cellular telephone, a smartphone, a tablet, a netbook, a wirelessterminal, a laptop computer, a wearable computer device, a femtocell, ahigh data rate (HDR) subscriber station, an access point, an accessterminal, or other personal communication system (PCS) device.

The communication station 1100 may include communications circuitry 1102and a transceiver 1110 for transmitting and receiving signals to andfrom other communication stations using one or more antennas 1101. Thecommunications circuitry 1102 may include circuitry that can operate thephysical layer (PHY) communications and/or medium access control (MAC)communications for controlling access to the wireless medium, and/or anyother communications layers for transmitting and receiving signals. Thecommunication station 1100 may also include processing circuitry 1106and memory 1108 arranged to perform the operations described herein. Insome embodiments, the communications circuitry 1102 and the processingcircuitry 1106 may be configured to perform the operations detailed inFIGS. 2-10.

In accordance with some embodiments, the communications circuitry 1102may be arranged to contend for a wireless medium and configure frames orpackets for communicating over the wireless medium. The communicationscircuitry 1102 may be arranged to transmit and receive signals. Thecommunications circuitry 1102 may also include circuitry formodulation/demodulation, upconversion/downconversion, filtering,amplification, etc. In some embodiments, the processing circuitry 1106of the communication station 1100 may include one or more processors. Inother embodiments, two or more antennas 1101 may be coupled to thecommunications circuitry 1102 arranged for sending and receivingsignals. The memory 1108 may store information for configuring theprocessing circuitry 1106 to perform operations for configuring andtransmitting message frames and performing the various operationsdescribed herein. The memory 1108 may include any type of memory,including non-transitory memory, for storing information in a formreadable by a machine (e.g., a computer). For example, the memory 1108may include a computer-readable storage device, read-only memory (ROM),random-access memory (RAM), magnetic disk storage media, optical storagemedia, flash-memory devices and other storage devices and media.

In some embodiments, the communication station 1100 may be part of aportable wireless communication device, such as a personal digitalassistant (PDA), a laptop or portable computer with wirelesscommunication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, an instant messaging device, adigital camera, an access point, a television, a medical device (e.g., aheart rate monitor, a blood pressure monitor, etc.), a wearable computerdevice, or another device that may receive and/or transmit informationwirelessly.

In some embodiments, the communication station 1100 may include one ormore antennas 1101. The antennas 1101 may include one or moredirectional or omnidirectional antennas, including, for example, dipoleantennas, monopole antennas, patch antennas, loop antennas, microstripantennas, or other types of antennas suitable for transmission of RFsignals. In some embodiments, instead of two or more antennas, a singleantenna with multiple apertures may be used. In these embodiments, eachaperture may be considered a separate antenna. In some multiple-inputmultiple-output (MIMO) embodiments, the antennas may be effectivelyseparated for spatial diversity and the different channelcharacteristics that may result between each of the antennas and theantennas of a transmitting station.

In some embodiments, the communication station 1100 may include one ormore of a keyboard, a display, a non-volatile memory port, multipleantennas, a graphics processor, an application processor, speakers, andother mobile device elements. The display may be an LCD screen includinga touch screen.

Although the communication station 1100 is illustrated as having severalseparate functional elements, two or more of the functional elements maybe combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs) and/or other hardware elements. Forexample, some elements may include one or more microprocessors, DSPs,field-programmable gate arrays (FPGAs), application specific integratedcircuits (ASICs), radio-frequency integrated circuits (RFICs), andcombinations of various hardware and logic circuitry for performing atleast the functions described herein. In some embodiments, thefunctional elements of the communication station 1100 may refer to oneor more processes operating on one or more processing elements.

Certain embodiments may be implemented in one or a combination ofhardware, firmware, and software. Other embodiments may also beimplemented as instructions stored on a computer-readable storagedevice, which may be read and executed by at least one processor toperform the operations described herein. A computer-readable storagedevice may include any non-transitory memory mechanism for storinginformation in a form readable by a machine (e.g., a computer). Forexample, a computer-readable storage device may include read-only memory(ROM), random-access memory (RAM), magnetic disk storage media, opticalstorage media, flash-memory devices, and other storage devices andmedia. In some embodiments, the communication station 1100 may includeone or more processors and may be configured with instructions stored ona computer-readable storage device.

FIG. 12 illustrates a block diagram of an example of a machine 1200 orsystem upon which any one or more of the techniques (e.g.,methodologies) discussed herein may be performed. In other embodiments,the machine 1200 may operate as a standalone device or may be connected(e.g., networked) to other machines. In a networked deployment, themachine 1200 may operate in the capacity of a server machine, a clientmachine, or both in server-client network environments. In an example,the machine 1200 may act as a peer machine in peer-to-peer (P2P) (orother distributed) network environments. The machine 1200 may be apersonal computer (PC), a tablet PC, a set-top box (STB), a personaldigital assistant (PDA), a mobile telephone, a wearable computer device,a web appliance, a network router, a switch or bridge, or any machinecapable of executing instructions (sequential or otherwise) that specifyactions to be taken by that machine, such as a base station. Further,while only a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein, such as cloudcomputing, software as a service (SaaS), or other computer clusterconfigurations.

Examples, as described herein, may include or may operate on logic or anumber of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operationswhen operating. A module includes hardware. In an example, the hardwaremay be specifically configured to carry out a specific operation (e.g.,hardwired). In another example, the hardware may include configurableexecution units (e.g., transistors, circuits, etc.) and acomputer-readable medium containing instructions where the instructionsconfigure the execution units to carry out a specific operation when inoperation. The configuring may occur under the direction of theexecution units or a loading mechanism. Accordingly, the execution unitsare communicatively coupled to the computer-readable medium when thedevice is operating. In this example, the execution units may be amember of more than one module. For example, under operation, theexecution units may be configured by a first set of instructions toimplement a first module at one point in time and reconfigured by asecond set of instructions to implement a second module at a secondpoint in time.

The machine (e.g., computer system) 1200 may include a hardwareprocessor 1202 (e.g., a central processing unit (CPU), a graphicsprocessing unit (GPU), a hardware processor core, or any combinationthereof), a main memory 1204 and a static memory 1206, some or all ofwhich may communicate with each other via an interlink (e.g., bus) 1208.The machine 1200 may further include a power management device 1232, agraphics display device 1210, an alphanumeric input device 1212 (e.g., akeyboard), and a user interface (UI) navigation device 1214 (e.g., amouse). In an example, the graphics display device 1210, thealphanumeric input device 1212, and the UI navigation device 1214 may bea touch screen display. The machine 1200 may additionally include astorage device (i.e., drive unit) 1216, a signal generation device 1218(e.g., a speaker), an OFDMA uplink resource allocation device 1219, anetwork interface device/transceiver 1220 coupled to antenna(s) 1230,and one or more sensors 1228, such as a global positioning system (GPS)sensor, a compass, an accelerometer, or other sensor. The machine 1200may include an output controller 1234, such as a serial connection(e.g., universal serial bus (USB), parallel, or other wired or wireless(e.g., infrared (IR), near field communication (NFC), etc.) tocommunicate with or control one or more peripheral devices (e.g., aprinter, a card reader, etc.)).

The storage device 1216 may include a machine-readable medium 1222 onwhich is stored one or more sets of data structures or instructions 1224(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 1224 may alsoreside, completely or at least partially, within the main memory 1204,within the static memory 1206, or within the hardware processor 1202during execution thereof by the machine 1200. In an example, one or anycombination of the hardware processor 1202, the main memory 1204, thestatic memory 1206, or the storage device 1216 may constitutemachine-readable media.

The OFDMA uplink resource allocation device 1219 may carry out orperform any of the operations and processes described and shown above.For example, the OFDMA uplink resource allocation device 1219 may beconfigured to enable a two-phase UL MU transmission, a resourceallocation phase, and a data transmission phase. The first phase(resource request phase) may be triggered by the AP, where the AP mayask devices to send a specific signal with UL OFDMA if they want to havea transmit opportunity in the second phase or in future UL MUtransmissions. The characteristics of the signal sent by the devices mayenable the AP to identify the devices if they are associated devices orknow that unassociated devices sent a signal with randomcharacteristics. The OFDMA uplink resource allocation device 1219 may beconfigured to define the signal as a code sequence (line of theP-matrix) of the HE-LTF, sent on only a resource unit in frequency (26tones allocation) using UL OFDMA. This combination of a code andfrequency resource unit may have an ID, which is called the resourceblock ID (RBID). The energy detection of code and frequency unit (RBID)enables the AP to know the identity of the device. The AP canacknowledge to the devices that it received the resource requests. Thesecond phase is a regularly scheduled UL MU transmission, which startswith a trigger frame sent by the AP, announcing the identity of thedevices that will transmit in the UL MU transmission, and otherinformation like the allocated resources.

While the machine-readable medium 1222 is illustrated as a singlemedium, the term “machine-readable medium” may include a single mediumor multiple media (e.g., a centralized or distributed database, and/orassociated caches and servers) configured to store the one or moreinstructions 1224.

Various embodiments may be implemented fully or partially in softwareand/or firmware. This software and/or firmware may take the form ofinstructions contained in or on a non-transitory computer-readablestorage medium. Those instructions may then be read and executed by oneor more processors to enable performance of the operations describedherein. The instructions may be in any suitable form, such as but notlimited to source code, compiled code, interpreted code, executablecode, static code, dynamic code, and the like. Such a computer-readablemedium may include any tangible non-transitory medium for storinginformation in a form readable by one or more computers, such as but notlimited to read-only memory (ROM), random access memory (RAM), magneticdisk storage media, optical storage media, a flash memory, etc.

The term “machine-readable medium” may include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine 1200 and that cause the machine 1200 to perform any one ormore of the techniques of the present disclosure, or that is capable ofstoring, encoding, or carrying data structures used by or associatedwith such instructions. Non-limiting machine-readable medium examplesmay include solid-state memories and optical and magnetic media. In anexample, a massed machine-readable medium includes a machine-readablemedium with a plurality of particles having resting mass. Specificexamples of massed machine-readable media may include non-volatilememory, such as semiconductor memory devices (e.g., electricallyprogrammable read-only memory (EPROM), or electrically erasableprogrammable read-only Memory (EEPROM)) and flash memory devices;magnetic disks, such as internal hard disks and removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 1224 may further be transmitted or received over acommunications network 1226 using a transmission medium via the networkinterface device/transceiver 1220 utilizing any one of a number oftransfer protocols (e.g., frame relay, internet protocol (IP),transmission control protocol (TCP), user datagram protocol (UDP),hypertext transfer protocol (HTTP), etc.). Example communicationsnetworks may include a local area network (LAN), a wide area network(WAN), a packet data network (e.g., the Internet), mobile telephonenetworks (e.g., cellular networks), plain old telephone service (POTS)networks, wireless data networks (e.g., Institute of Electrical andElectronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®,IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 familyof standards, and peer-to-peer (P2P) networks, among others. In anexample, the network interface device/transceiver 1220 may include oneor more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or oneor more antennas to connect to the communications network 1226. In anexample, the network interface device/transceiver 1220 may include aplurality of antennas to wirelessly communicate using at least one ofsingle-input multiple-output (SIMO), multiple-input multiple-output(MIMO), or multiple-input single-output (MISO) techniques. The term“transmission medium” shall be taken to include any intangible mediumthat is capable of storing, encoding, or carrying instructions forexecution by the machine 1200 and includes digital or analogcommunications signals or other intangible media to facilitatecommunication of such software.

In example embodiments of the disclosure, there may be an access point,comprising at least one memory storing computer-executable instructions;and at least one processor configured to access the at least one memory,wherein the at least one processor is configured to execute thecomputer-executable instructions to cause to send a trigger frame to afirst device; receive an uplink bandwidth resource request from thefirst device, in response to sending the trigger frame; determine a highefficiency-long training field (HE-LTF) in the uplink bandwidth resourcerequest; cause to send an uplink multiuser trigger frame; and identifyan uplink frame received from the first device.

Implementations may include one or more of the following features. Insome implementations, the access point may comprise at least onetransceiver configured to transmit and receive wireless signals. Theaccess point may comprise at least one antenna coupled to the at leastone transceiver configured to dissipate and detect electromagneticenergy associated with transmitting the wireless signals and receivingthe wireless signals respectively.

The at least one processor of the access point may be configured toexecute the computer-executable instructions to determine a highefficiency-short training field (HE-STF) in the uplink bandwidthresource request from the first device. The at least one processor maybe further configured to execute the computer-executable instructions toset an automatic gain control (AGC) based at least in part on theHE-STF. The HE-LTF may be received on a resource unit (RU) with acorresponding frequency code. The HE-LTF may be received on an RUassociated with a time code corresponding to at least one orthogonalfrequency division multiple access (OFDMA) symbol.

In some example embodiments, there may be a non-transitorycomputer-readable medium storing computer-executable instructions whichwhen executed by at least one processor results in performing operationscomprising: causing to send a trigger frame to a first device; receivingan uplink bandwidth resource request from the first device, in responseto sending the trigger frame; determining a high efficiency-longtraining field (HE-LTF) in the uplink bandwidth resource request;causing to send an uplink multiuser trigger frame; and identifying a ULframe from the first device.

Implementations may include one or more of the following features. Theat least one processor may be configured to execute thecomputer-executable instructions to determine a high efficiency-shorttraining field (HE-STF) in the uplink bandwidth resource request fromthe first device. The at least one processor may be configured toexecute the computer-executable instructions to set an automatic gaincontrol (AGC) based at least in part on the HE-STF. The HE-LTF may bereceived on a resource unit (RU) with a corresponding frequency code.The HE-LTF may be received on an RU associated with a time codecorresponding to at least one orthogonal frequency division multipleaccess (OFDMA) symbol.

In some example embodiments, there may be a device comprising at leastone memory storing computer-executable instructions; and at least oneprocessor configured to access the at least one memory, wherein the atleast one processor is configured to execute the computer-executableinstructions to receive a trigger frame from an access point (AP);determine that the device is associated with the AP; select a resourceunit (RU) and a corresponding code from a set of RUs assigned toassociated devices; determine a transmission power level correspondingto the code; and transmit the uplink bandwidth resource request.

Implementations may include one or more of the following features. Thedevice may further comprise at least one transceiver configured totransmit and receive wireless signals. The device may further compriseat least one antenna coupled to the at least one transceiver configuredto dissipate and detect electromagnetic energy associated withtransmitting the wireless signals and receiving the wireless signalsrespectively.

The HE-LTF may be transmitted in an uplink bandwidth request. The atleast one processor of the device may be further configured to executethe computer-executable instructions to cause the at least one processorto transmit the HE-LTF using the RU. The corresponding code may betransmitted in the HE-LTF. The at least one processor may be furtherconfigured to execute the computer-executable instructions to cause theat least one processor to transmit an HE-STF. The at least one processormay be further configured to execute the computer-executableinstructions to cause the at least one processor to transmit the HE-STFusing a cyclic shift diversity (CSD) value.

In some example embodiments, there may be a non-transitorycomputer-readable medium storing computer-executable instructions whichwhen executed by at least one processor results in performing operationscomprising receiving a trigger frame from an AP for an uplink bandwidthresource request; determining that a device is associated with the AP;selecting an RU and a corresponding code from a set of RUs assigned toassociated devices; determining a transmission power level correspondingto the code; determining that a legacy preamble should not be includedin the uplink bandwidth resource request; and transmitting the uplinkbandwidth resource request.

The operations and processes described and shown above may be carriedout or performed in any suitable order as desired in variousimplementations. Additionally, in certain implementations, at least aportion of the operations may be carried out in parallel. Furthermore,in certain implementations, less than or more than the operationsdescribed may be performed.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. The terms “computing device,” “userdevice,” “communication station,” “station,” “handheld device,” “mobiledevice,” “wireless device” and “user equipment” (UE) as used hereinrefers to a wireless communication device such as a cellular telephone,a smartphone, a tablet, a netbook, a wireless terminal, a laptopcomputer, a femtocell, a high data rate (HDR) subscriber station, anaccess point, a printer, a point of sale device, an access terminal, orother personal communication system (PCS) device. The device may beeither mobile or stationary.

As used within this document, the term “communicate” is intended toinclude transmitting, or receiving, or both transmitting and receiving.This may be particularly useful in claims when describing theorganization of data that is being transmitted by one device andreceived by another, but only the functionality of one of those devicesis required to infringe the claim. Similarly, the bidirectional exchangeof data between two devices (both devices transmit and receive duringthe exchange) may be described as “communicating,” when only thefunctionality of one of those devices is being claimed. The term“communicating” as used herein with respect to a wireless communicationsignal includes transmitting the wireless communication signal and/orreceiving the wireless communication signal. For example, a wirelesscommunication unit, which is capable of communicating a wirelesscommunication signal, may include a wireless transmitter to transmit thewireless communication signal to at least one other wirelesscommunication unit, and/or a wireless communication receiver to receivethe wireless communication signal from at least one other wirelesscommunication unit.

The term “access point” (AP) as used herein may be a fixed station. Anaccess point may also be referred to as an access node, a base station,or some other similar terminology known in the art. An access terminalmay also be called a mobile station, user equipment (UE), a wirelesscommunication device, or some other similar terminology known in theart. Embodiments disclosed herein generally pertain to wirelessnetworks. Some embodiments may relate to wireless networks that operatein accordance with one of the IEEE 802.11 standards.

Some embodiments may be used in conjunction with various devices andsystems, for example, a personal computer (PC), a desktop computer, amobile computer, a laptop computer, a notebook computer, a tabletcomputer, a server computer, a handheld computer, a handheld device, apersonal digital assistant (PDA) device, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, a consumerdevice, a non-mobile or non-portable device, a wireless communicationstation, a wireless communication device, a wireless access point (AP),a wired or wireless router, a wired or wireless modem, a video device,an audio device, an audio-video (A/V) device, a wired or wirelessnetwork, a wireless area network, a wireless video area network (WVAN),a local area network (LAN), a wireless LAN (WLAN), a personal areanetwork (PAN), a wireless PAN (WPAN), and the like.

Some embodiments may be used in conjunction with one way and/or two-wayradio communication systems, cellular radio-telephone communicationsystems, a mobile phone, a cellular telephone, a wireless telephone, apersonal communication system (PCS) device, a PDA device whichincorporates a wireless communication device, a mobile or portableglobal positioning system (GPS) device, a device which incorporates aGPS receiver or transceiver or chip, a device which incorporates an RFIDelement or chip, a multiple input multiple output (MIMO) transceiver ordevice, a single input multiple output (SIMO) transceiver or device, amultiple input single output (MISO) transceiver or device, a devicehaving one or more internal antennas and/or external antennas, digitalvideo broadcast (DVB) devices or systems, multi-standard radio devicesor systems, a wired or wireless handheld device, e.g., a smartphone, awireless application protocol (WAP) device, or the like.

Some embodiments may be used in conjunction with one or more types ofwireless communication signals and/or systems following one or morewireless communication protocols, for example, radio frequency (RF),infrared (IR), frequency-division multiplexing (FDM), orthogonal FDM(OFDM), time-division multiplexing (TDM), time-division multiple access(TDMA), extended TDMA (E-TDMA), general packet radio service (GPRS),extended GPRS, code-division multiple access (CDMA), wideband CDMA(WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA,multi-carrier modulation (MDM), discrete multi-tone (DMT), Bluetooth®,global positioning system (GPS), Wi-Fi, Wi-Max, ZigBee, ultra-wideband(UWB), global system for mobile communications (GSM), 2G, 2.5G, 3G,3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, long termevolution (LTE), LTE advanced, enhanced data rates for GSM Evolution(EDGE), or the like. Other embodiments may be used in various otherdevices, systems, and/or networks.

Certain aspects of the disclosure are described above with reference toblock and flow diagrams of systems, methods, apparatuses, and/orcomputer program products according to various implementations. It willbe understood that one or more blocks of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and the flowdiagrams, respectively, may be implemented by computer-executableprogram instructions. Likewise, some blocks of the block diagrams andflow diagrams may not necessarily need to be performed in the orderpresented, or may not necessarily need to be performed at all, accordingto some implementations.

These computer-executable program instructions may be loaded onto aspecial-purpose computer or other particular machine, a processor, orother programmable data processing apparatus to produce a particularmachine, such that the instructions that execute on the computer,processor, or other programmable data processing apparatus create meansfor implementing one or more functions specified in the flow diagramblock or blocks. These computer program instructions may also be storedin a computer-readable storage media or memory that may direct acomputer or other programmable data processing apparatus to function ina particular manner, such that the instructions stored in thecomputer-readable storage media produce an article of manufactureincluding instruction means that implement one or more functionsspecified in the flow diagram block or blocks. As an example, certainimplementations may provide for a computer program product, comprising acomputer-readable storage medium having a computer-readable program codeor program instructions implemented therein, said computer-readableprogram code adapted to be executed to implement one or more functionsspecified in the flow diagram block or blocks. The computer programinstructions may also be loaded onto a computer or other programmabledata processing apparatus to cause a series of operational elements orsteps to be performed on the computer or other programmable apparatus toproduce a computer-implemented process such that the instructions thatexecute on the computer or other programmable apparatus provide elementsor steps for implementing the functions specified in the flow diagramblock or blocks.

Accordingly, blocks of the block diagrams and flow diagrams supportcombinations of means for performing the specified functions,combinations of elements or steps for performing the specified functionsand program instruction means for performing the specified functions. Itwill also be understood that each block of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and flowdiagrams, may be implemented by special-purpose, hardware-based computersystems that perform the specified functions, elements or steps, orcombinations of special-purpose hardware and computer instructions.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainimplementations could include, while other implementations do notinclude, certain features, elements, and/or operations. Thus, suchconditional language is not generally intended to imply that features,elements, and/or operations are in any way required for one or moreimplementations or that one or more implementations necessarily includelogic for deciding, with or without user input or prompting, whetherthese features, elements, and/or operations are included or are to beperformed in any particular implementation.

Many modifications and other implementations of the disclosure set forthherein will be apparent having the benefit of the teachings presented inthe foregoing descriptions and the associated drawings. Therefore, it isto be understood that the disclosure is not to be limited to thespecific implementations disclosed and that modifications and otherimplementations are intended to be included within the scope of theappended claims. Although specific terms are employed herein, they areused in a generic and descriptive sense only and not for purposes oflimitation.

What is claimed is:
 1. A device for soliciting uplink multiusertransmissions, the device comprising processing circuitry coupled tostorage, the processing circuitry configured to: determine a triggerframe associated with one or more resource allocations, wherein thetrigger frame indicates a plurality of resource units (RUs); determine afirst transmission power level and a second transmission power levelcorresponding to the trigger frame; allocate a first RU to a firststation device and a second RU to a second station device; cause to sendthe trigger frame to the first station device and to the second stationdevice, wherein the trigger frame comprises a first indication of thefirst transmission power level, a second indication of the first RU, athird indication of the second transmission power level, and a fourthindication of the second RU, and wherein the first RU is different fromthe second RU; identify an uplink frame, of the multiuser transmissions,received from the first station device, wherein the uplink frame is anuplink bandwidth resource request comprising a high efficiency-longtraining field (HE-LTF), and wherein the high efficiency-long trainingfield (HE-LTF) is received at the first RU of the plurality of RUs; andwherein the uplink frame comprises a parameter indicating a power levelused by the first station device, wherein the power level is based onthe first indication of the first transmission power level of thetrigger frame.
 2. The device of claim 1, wherein the trigger framecomprises an allocation subfield indicating at least one of the one ormore resource allocations associated with one or more channels.
 3. Thedevice of claim 1, wherein the processing circuitry is furtherconfigured to identify a short training field of the uplink frame. 4.The device of claim 1, wherein the first transmission power level isencoded in a subfield of the trigger frame, wherein the subfieldindicates a transmission power level for a channel of one or morechannels.
 5. The device of claim 3, wherein the processing circuitry isfurther configured to adjust an automatic gain control (AGC) of anantenna of the device based on the short training field.
 6. The deviceof claim 1, further comprising a transceiver configured to transmit andreceive wireless signals.
 7. The device of claim 6, further comprisingan antenna coupled to the transceiver.
 8. A non-transitorycomputer-readable medium storing computer-executable instructions whichwhen executed by one or more processors result in performing operationscomprising: determining a trigger frame associated with one or moreresource allocations, wherein the trigger frame indicates a plurality ofresource units (RUs); determining a first transmission power level and asecond transmission power level corresponding to the trigger frame;allocating a first RU to a first station device and a second RU to asecond station device; causing to send the trigger frame to the firststation device and to the second station device, wherein the triggerframe comprises a first indication of the first transmission powerlevel, a second indication of the first RU, a third indication of thesecond transmission power level, and a fourth indication of the secondRU, and wherein the first RU is different from the second RU;identifying an uplink frame, of multiuser transmissions, received fromthe first station device, wherein the uplink frame is an uplinkbandwidth resource request comprising a high efficiency-long trainingfield (HE-LTF), and wherein the high efficiency-long training field(HE-LTF) is received at the first RU of the plurality of RUs; andwherein the uplink frame comprises a parameter indicating a power levelused by the first station device, wherein the power level is based onthe first indication of the first transmission power level of thetrigger frame.
 9. The non-transitory computer-readable medium of claim8, wherein the trigger frame comprises an allocation subfield indicatingat least one of the one or more resource allocations associated with oneor more channels.
 10. The non-transitory computer-readable medium ofclaim 8, wherein the operations further comprise identifying a shorttraining field of the uplink frame.
 11. The non-transitorycomputer-readable medium of claim 8, wherein the first transmissionpower level is encoded in a subfield of the trigger frame, wherein thesubfield indicates a transmission power level for a channel of one ormore channels.
 12. The non-transitory computer-readable medium of claim10, wherein the operations further comprise adjusting an automatic gaincontrol (AGC) of an antenna based on the short training field.
 13. Amethod comprising: determining, by one or more processors, a triggerframe associated with one or more resource allocations, wherein thetrigger frame indicates a plurality of resource units (RUs); determininga first transmission power level and a second transmission power levelcorresponding to the trigger frame; allocating a first RU to a firststation device and a second RU to a second station device; causing tosend the trigger frame to the first station device and to the secondstation device, wherein the trigger frame comprises a first indicationof the first transmission power level, a second indication of the firstRU, a third indication of the second transmission power level, and afourth indication of the second RU, and wherein the first RU isdifferent from the second RU; identifying an uplink frame, of multiusertransmissions, received from the first station device, wherein theuplink frame is an uplink bandwidth resource request comprising a highefficiency-long training field (HE-LTF), and wherein the highefficiency-long training field (HE-LTF) is received at the first RU ofthe plurality of RUs; and wherein the uplink frame comprises a parameterindicating a power level used by the first station device, wherein thepower level is based on the first indication of the first transmissionpower level of the trigger frame.
 14. The method of claim 13, whereinthe trigger frame comprises an allocation subfield indicating at leastone of the one or more resource allocations associated with one or morechannels.